Delinquent sensors and schizophrenic materials: using molecular switches to make materials with multiple personalities

Abstract

In this paper, we consider the use of ‘adaptive’ materials (i.e. materials that can be switched reversibly between two or more different forms with radically different characteristics). This may open the way to the development of materials that can exist in a passive form (non-binding) until a measurement is required, at which point the material is switched to an ‘active’ form. Binding then occurs and a signal is generated, and the material subsequently switched back to the ‘passive’ form. We have demonstrated that binding of metal ions and amino acids at spiropyran modified surfaces can be controlled photonically using LEDs. It is possible that this may provide a route to more sophisticated materials whose host-guest binding behaviour and signal generation can be activated or deactivated on demand. This effect has important potential applications in sensors, purification resins, separation science and drug delivery. In this paper we report progress on the modification of several materials with spiropyran and their incorporation within microfluidic devices.